Can blank and method of producing same



I 26, 1939. w E, ,'GRPE 2,174,071

' CAN BLANK AND METHOD oF-PnoDUcING Smm I l Fila@v Aprilv 29, 1937 .o n Tr N me V NF .w lm A Patented Sept. 26, 1939 PATENT oFFi'cE 2,174,071 CAN BLANK AND IWSETHOD F PRODUCING William F. Grupo, Lyndhurst, N. J., assignor to Chambon Corporation, Garfield, N. J., a corporation of New York Application April 29, 1937, Serial No. 139,793 19 claims. (c1. :i1-168.2)

vThis invention relates to the art of manufacturing sheet Imetal containers ofthe type'ordi-- narily known as "tin cans, and particularly to a method of producing novel sheet metal blanks applicable in the art. The present application is a continuation in part of application Serial No. 63,594, illed February 12, 1936.

'Ihe invention achieves considerable economies in the art by: y 1.-Making available a raw material possessing highly desirable characteristics but heretofore c impractical of-use in its most desirable web form.

2.--Aifording a method of producing sheet metal'blanks continuously from the web of raw mam terial.

3.-Providing an improved sheet metal blank at a cost lower` than heretofore.

Black iron, pack-rolled in individual sheets, is the base material ordinarily and commercially 20 used ,for blanks in the can-making industry. The

sheets are protectively coated with tin over their entire surface area by dipping in a bath of molten tin; That which is to become the in ner surface of the cans may be additionally coated with a non-metallic protective lining, the opposite sury yface being usually imprinted with designating and/or design material, or being left for the reception o! individual can labels. Proper portions Aof the tin coating are left uncovered byother coating `or imprinting material to provide areas for soldering atthe seam location of the manui'actured can body. The prepared black iron sheets are cut into individual can blanks.

'I'he methodof this invention preferably employs cold-rolled steel sheet in web form as the raw material'for the can blanks. Rolls of coldrolled steel in web form are commercially available at a cost lower than black iron sheets. Because of its uniform texture and characteristic hardness, cold-rolled steel has a much greater Vstrength than does pack-rolled black iron. But,

in spite of its obvious advantages, cold-rolled' steel in web iorm has never heretofore been sucties which have heretofore prevented'the use of cold-rolled steel in web form as theraw material for tincans, and have departed altogether from the customary process of manufacturing tin can j -fbnnks and from the ordinary methods of applying tin to cold-rolled steel. I have accomplished this by providing a new-process which, besides having the advantages of making available to the art this desirable raw material, of coating requisite areas with a verythin and uniform' layer of 5 tin, and of making possible complete protection of the base metal of the blank, has the additional advantage of being much more economical than Athe old processes because it is continuous in operation and effects a. considerable saving of tin. i0

A complete and practical procedure in the present method consists in operating in a. continuous manner upon a traveling web of cold-rolled steel in steps to effectthe following results: (1) the electrolytic deposition of tin solely. at localized 15 areas on the surface of -the web for service as component portions of the soldered seam -of the resulting can body; (2) the application of a. protective lining to one facefof the web, slightly, but positively, overlapping the tinned areas which o otherwise are left entirely uncovered; (3) the application of a protective, decorative and/or desig natory coating to the opposite face of the web,

slightly, but positively, overlapping the tinned areas which otherwise are left entirely uncovered; (4) the severing of the individual can blanks from the web.

By ilrst' applying tin over the requisite narrow band areas of the base metal and subsequently protectively coating the-intermediate u'ntinned 30 areas thereof, the latter coating slightly, but positively overlapping' the tinned areas, complete y, superficial protection o the `base metal is aiorded; Any possible zones of danger, from a. protec- 'tive standpoint,- that might exist by reason of 35 incomplete joinder between tinned areas and ,otherwise protectively coated areas of the base metal, were there no provision of overlap, are eiectively eliminated.

The web may' have a width equal to the width o of the resulting blank. In this case ity is preferable that-thetinned areas be disposed proximate the lateral edges of the web and` on both surfaces thereof in the form of respective, continuous, narrow bands substantially .parallel with the stated lateral edges and having av width extending inwardly of the web anddetermned in dimension by therequisites ofthe soldered seam of the desired can body.` The individual;widthv of the strips will always; be considerablytless than the -width oi theweb.h4 v .l y The web` mayhave a widthtwo or more times the desired width ofthe resulting blanks.` 'In this case the tinn'ed areas may be disposed proximate the lateral edges of the web as above explained,

A are severed from the the peculiar disposition ,a pending upon the desired and additional tinned areas in the form of continuous strips parallel to the' lateral edge strips, and usually double' the width of each, may be interposed at appropriate intermediate l tions on both faces-of the web, the exact locations dewidth oi .the resulting blanks. l

In the first instance, the blanks are Vsevered from the web as by making consecutive single cuts, transversely of the web, the distance ibetween cuts determining the height of theA resulting can body. l

In the second instance, the individual blanks web, as by making continuous longitudinal cuts dividing the stated intermediate strips, and by making consecutive single cuts transversely` of the web.

'I'he rst step of this process, and particularly of the eiectrolytically deposited tin, overcomes thel difficulties heretofore encountered in attempting to satisfactorily tin cold-rolled steel. While molten tin cannot satisfactorily be mechanically applied to the smooth surface f cold-rolled steel even after cleaning.

and electrolytic deposition over thefull faces of the web is not uniform as required, I have found thatif the grease be removed` from the surface of the steel by a suitable cleansing bath such as an ordinary cyanide bath, it is possible to obtain perfect intimate adherence and a very thin uniform spread of tin by electrolytic deposition over narrow band areas of the cleansed surface. Most desirably, the deposition is affected as follows: A travelling webof cold-rolled steel is after cleansing, through a bath of suitable electrolyte. While in the bath, the not-to-be-tinned areas of the ,web between the narrow bandfareas to be tinned are protected from electrolytic deposition, as by endless rubber shields which lie against and travel with each portion of the web while it is in the bath and separate from it as lit leaves the bath.-

The second and third steps of the process may be carried out economically by means of any of the' many coating and printing devices adapted to operate upon a travelin'gweb.v

A blank produced by this method has'a body of cold-rolled sheet steel of great strength and even texture. The sheet steel body is covered by uniformly thin, closely and strongly adhering, electrolytic deposits of tin solely at localised narrow band'areas which' are to become component portions of the soldered seam of the resulting can body. Thesurface of the blank which is to become the inner face of the can body iscoatecl` with a protective lining leaving' the tinned areas entirely uncovered except for a slight, but posi- Q tive, overlap along the lines of joinder between the intermediate protectively coated areas and the narrow band tinned areas. The surface of the blank which is to become the outer face of the can body is m'otectively imprinted with designatory and/or design material in the same manner, or is protectively prepared over the sam area forthereceptionofalabel.

'rneusualbiank prepared pmuant terms method has its body 0f cold-rolled sheet steel covered -on both of its faces v`with electrolyticdeposits of tin extending solely over narrow band areas' proximate, respectively, two of the opposing end portions ofthe blank for serving as com'- ponent portions of the soldered seam of the manufactured can body, the surface areas intermediate the narrow band areas plus a slight. but

tinned layers andnon-metallic protective layers being exaggerated in Fig'. 2 for sake of clarity;

Fig. 3 is a plan view of a'portion of the metal web from which the blank shown in Figs. i and 2 may be produced;

Pig. 4 is a diagrammatic view illustrating ap' paratus suitable for carrying out a preferred procedure pursuant to the invention; and

Fig. 5 is 'a vertical section of Eg. 4.

In the specific method illustratedin the drawing,a long continuous strip or web of cold-rolled steel Ilisdrawnfrom aroll li throughacleansing apparatus A, an electro-plating apparatus B. a nnal cleansing apparatus C, a coating apparatus imprinting apparatus E, to' a severing ap paratus F. Continuous travel of the strip is effected by driving some or all of the rollers and pulleys over which the strip Il at advantageously a'uniform peripheral speed.

The cleansingapparatus A is of any suitable' is not necessary nor desirable that the smooth surface of the cold-rolled steel be roughened during this cleansing operation. Adhering liquid from the cyanide bath may be removed by suitable washing` treatment for priming the faces of gie strip vfor the succeeding electroplating opera- The electropiatlng apparatus B, which i`n itself constitutes part of my invention. serv'es to electrolytically deposit coatings of tin on a plurality of selected band-like areas. usually on both .sides of the strip. In the form illustrated, and considering a single face of the strip, two of the band-like areas, designated I2, I2, are located respectively, at the lateral edges of the strip, and a third band-like area, designated i3, extends along the middle line of the strip andis twice the width of the band-like areas at the edges of the strip,l as appears from Fig. 3.. The electroplating apparatus B, for depositing tin on the areas l2, I2 and I3 of both faces of the strip, as shown, includes a tank M, containing the electrolyte, means for guiding'the traveling strip Il into and out of the" the drawing, the traveling strip is directed into and out of the electrolyte by rollers II, IQ iournalled on the tank and dipping into the electrolyte, and by pulleys I1-I, "-2, I1-3 located above the tank. Each roller lt'as'shown, is'A formed of two separate parts mounted on a couvL mon shaft, as appears from 111g. 5.

Traveling rubber shields it, il and 2l, Il are provided ior protecting the intermediate areas Il, Il of both faces of the strip from electrolytic action. 'The shields it," may consist of rubber layers formedon the periphery of the two-part rollers ICJ, Each has a width equal to the widthof an intermediate area II of the strip.

These shields il, il protect the inner surface areaslkllofthestripfromelectrolyticaction' 2,174,071 while leavin the band-like areas I2. I2 of the Il, Il, with a slight, bi positive, overlapping of innersurfaceofthestrip toelectrolytic inkonthebandlikeareasi2,|2,andi3.

shields2l,2l,asshown.eonsistottwo rubberbands,eachguidedovertwopill lenwithinthetankand seu or modes 21,22 mi 2|. 2z ne located in' oppositely positioned band-like areas I2, I2 oi' the strip passing through the electrolyte. The modes-'2L 2| and 22, 22 have the form of bands of approximately the same width as the band-like areas I2, I2. Consequently, they do not interfere with the circulation of the electrolyte as would wide anodes, and, by their form, they concentrate the electrolytic action on the band-like areas I2, I2. A set of anodes 23 and 24 is provided `fox' effecting eleetroplating of the intermediate bandlike areas Il on both faces of the strip. The anode 2l, adjacent the outer surface ofthe bandlike area Il is shown placed between the actual shield locations of the travelingshields and the return reaches thereof, so that the latter do vnot interfere with the electrolytic action.

Electrical connections to the anode: and to the strip Il, which serves as a cathode, may be made in the conventional manner. For convenience, it is desirable that the electric circuit be `designed to maintain the strip Il at ground potential, so that insulating precautions need not be taken to safeguard the operators from electrical shock.

Beyond the electropating appar atus B, the traveling strip may be passed through a nal cleansing apparatus C, which comprises a tank 25, to wash it free from residue of the electrolyte.

Itmay thereafter be dried by passing it through a heater 25-l. v

The coating apparatus D and the printing apl Vparatus E may be of any conventional construction appropriate forvoperating upon a traveling web and may include heaters for drying the coatings applied. Means, such as the pulleys 26, are provided for reversing the strip aftergit passes through the coating apparatus D, so that the printing apparatus E may operate upon the side of thestrip opposite to that operated upon by the coating apparatus D.

The coating apparatus D applies `to one surface of the strip a. protective lining. such as a resinous coating. It is designed to apply this lining to the intermediate areas Ii, I5, with a slight, but positive, overlapping on the band-like areas I2, I2 and I3. g g

The printing. apparatus E applies to thev other side of the strip a decorative and protective coating which may be formed ofinks containing resinous or other film-forming binders. The plurality of printing rollers of the printing appa-' ratus E are designed to eect, by combined action, coatings of the entire intermediate areas.

The severing apparatus F, which is shown only diagrammatically, may be of, conventional construction. Such severing apparatus serves to severthestrip Ilalongthedotanddashlines 21, see Fig. 3, to divide it into can-blanks, such asthatshowninFigs. landz.`

Theblankshowninli'igs. 1and`2has abody consisting of a sheet of cold-rolled steel. At the lateral sides of'the sheet on each face are vnarrow band areas I2, I2, of uniformly thin, strongly adherent electrolytic deposits of tin. The area of one face of the sheet between these spaced band areas of tin coating has a protective nonmetallic lining 28, which slightly, but positively. overlaps adjacent edges of the stated band areas of tin coating. The corresponding area of the side. of the sheet' between its spa'cdband' I areas of tin coating has' a decorative and protective coating 2l,v which slightly, but positively,

overlaps adjacent edges of its stated band areas of tin coating. Thus. allaparts of the sheet are protected against oxidation, and tinned areas are provided solely at those portions of the blank which willserve as component members ofthe soldered seam of the manufactured container.

i In the case of processing a web of cold rolled steel, cleaning may advantageously be accomplished electrolytically prior to passage of the web through the electro-plating bath. An electrolytlc cleansing bath of common type utilizing the web as one electroterminal may be supplied in place of the .chemical cleansing bath illustrated at A, Fig. 4, c

Also, it may be desirable to burnish the incompletely plated surfaces of the traveling web as the latter passes through the electro-plating bath B, Fig. 4. This may be accomplished by mounting suitable means, such as agate stones, at various locations adjacent the path of travel ofthe web through the electro-plating bath, for light rubbing action over the incompletely plated surfaces. `Burnishing will remove any porous, spongy deposition of tin, that might tend to form on .the

surfaces undergoing plating, and will insure exposure ofra fresh polished surface at all times during the actual plating process.

While this invention is directed. primarily to making availableto the canning-industry coldrolled steel in web form as raw material for can blanks, inL its broadest aspect the invention includes the use of any type and character of sheet base material, suitable for can bodies, on which, solely at localized spaced band areas of its surface, a metallic solderfreceptive material may be electrolytically deposited in a uniformly thin, strongly adhering coating.

Whereas this invention has been described and illustrated with respect to a preferred form thereof, it should be clearly understood that; changes travel of the strip, and cutting the strip'into 75 amlying anon-metallic coating to the portim ofthestripwhichwasooveredbys'aldshield;

3.Amethodofmakinghlanksfor themanuiaetureofcontainerawhichcomprhesdirectlnga traveling strip of smooth-surfaced cold-rolled steelintoandoutofatin-depolitingelectrolytic bath.andproteeiingwidelongitudinalareasof bothmrfacesofthestripfromtheeleetrolyteso that tin is depositedin narrow widely-spaced band-likeareasonbothsidesofthestrip.

4 Amethodofmakingblanksforthemanufacture of containers. which comprises directing a traveling strip of smooth-surfaced cold-rolled steel into and out ofa tin-depositingcelectrolytic bath, protecting wide longitudinal areas of both surfacesofthestrlpfromtheelectrolytesothat tin is deposited in narrow widely-spaced band-like areasonbothsidesofthestrip,andthereafter applyillt a non-:metallic coating to the portionsof the strip which were protected from the electrolyte. I

5. A method of treating a continually traveling web of sheet metal which comprises electrolytically depositing a protective metallic coating solely over narrow band-like areas spaced relativetooneanotheronthesurfaceofthe web and extending continuously along the length of the web, while protecting the remaining surface of the web from electrolytic deposition by means independent of and separable from the so protected sm'face of the web.'l

6. A method of treating acontinually traveling web of -sheet metal which comprises submerging the .web at one stage of its travel in a metal-depositing bath; protecting continuous portions of the faces of the web along its length from metal adherence during travel through the said bath by means independent of and separable from the so protected faces, meanwhile allowing metal adherence. over continuous unprotected' portions along thelengthofthe web; andthereafter coating the protected portions of the faces of the web with a protective material. Y

7. A' method of treating a continually traveling web of sheet metal which comprises submerging the web at one stage of its travel in a metal-depositing bath; protecting continuous portions of the faces' 'of the web along its length from metal adherence during travel through the said bath by Y means independent of and separable-from the so protected faces. meanwhile allowing metal adherence, over continuous unprotected portions along the length of the web; and thereafter coating the protected portions of the faces of the web with a protective material which slightly overlaps the applied metal coatings along the lines of joinder therewith.

8; A method of producing blanks for the manufacture of containers which comprises, passing a' continually traveling web v of sheet metal throgh a solder-receptive-metal depositing electrolytic bath, meanwhile protecting from e i lytic deposition of metal thatportion of the surface 'area of the traveling area' of the blank not necessarily solder receptive web which forms the sreasofthehavelingwebwithanonmetallic protectivematerialwhichslightlyoverlapsvthe metaldepositionalongthelinesofprotectedareaofonefaceofthewebwithoa. Y protectiveliningmaterialwhichslightly overlaps thesaidhand-like areas ofdeposited'tinalong the lines of joinder therewith; protectively co'verlngthesoprotectedareaoftheotherfaceof theweb with deslgnatory and/oni ornamental ma-L terial which slightly overlaps the said band-like areasof depositedtinalongthelinesofjoinder therewith; and severing the individual blanks from the traveling web.

1o. A can blankmnsisdng or a. sheet of mem,A

having narrow bands of solder-receptive material extending along opposite marginal edge portions on both sides, and non-metallic coatings extending between said bands and slightly overlapping the inner edges ofthe said bands.

^ 11. A can blank consisting of a havim narrow bands of solder-receptive metal sheet-of niml' extending along opposite' marginal edge portions f on both sides, and non-metallic coatings extendingV between said bands and slightly overlapping the inner edges of the said bands.

12. A blank for the-manufacture of containers. comprising a sheet of metal having solely those portions which will serve of the to-be-soldered seam of container, coated, respectively, with narrow bands of intimately adhering, uniformly thin, electrolytic deposits of soder-receptive metall, andfhaving the remaining area of its faces coated with a nonmetallic protective material which slightly over,

laps said narrow bands of deposited solder-receptive metal along the lines of joinder therewith.

13. A blank for the manufacture of containers,

comprising a sheet of metal having solely those serve as component members portions which will of the to-be-soldered seam ofthe manufactured container, coated, respectively with narrow hands of soldered-receptive metal, and having the remining area of its mees coated with a non-metallic protective material which slightly overlaps said narrow bands of deposited soldered-receptive metal along the lines of ioinder therewith.

14. A web for the production of container blanks, comprising a sheet of base metal, tin.-

coating applied t'o said web at its portions disposed immediately adjacent opposite edges thereas component members the manufactured.

of/and onhoth faces of the web and extending about both said edges, and tin-coated portions' of the web disposed intermediate said first named tin-coated portionsand on both faces of the web,

said tin-coating .serving as the to-be-soldered areas,theremainderofthefacialareasofboth faces of the web being free from tin, one face of'the web having varnish or equivalent -applied@ over the whole of the remainder of its said face between its said tin-coated portions.

15. A web for the production of container blanks, comprising a sheet of base metal, tincoating applied to said web at its portions disposed immediately adjacent opposite edges thereof and on both faces of the web and yextending about both said edges, and tin-coated portions of the web disposed intermediate said rst named tin-coated portions and on both faces of the web, said tin-coatings serving as the to-be-soldered areas, the remainder of the facial areas of both faces of the web being free from tin, one face of the web having varnish or equivalent applied over the whole of the remainder of its said face between its said tin-coated portions, the other face of the web having decoration applied thereto.

16. A blank for the production of a container, comprising a sheet of base metal, tin-coating applied to said blank at its portions disposed immediately adjacent opposite edges thereof and on both faces of the blank and extending about both said edges, said tin-coating serving as the to-besolderedareas, the remainder of the facial area on one face of the blank being free from tin, said one facerof the blank having varnish or equivalent applied over the whole of the remainder of its said face between its said tin-coated portions.

17. A blank for the production of a container, comprising a sheet of base metal, tin-coating applied to said blank at its portions disposed immediately adjacent opposite edges thereof and on both faces of the blank and extending about both of both faces of the blank being free from tin,A

one face of the blank having varnish or equivalent applied over the whole of the remainder of its said face between its said tin-coated prtions,'

the other face of the blank having decoration applied thereto.

18. A method of treating a continually travelling web of sheet metal, which"comprises submerging the web at one stage of its travel in a metal depositing bath;` protecting a continuous portion of at least one face of the web along its length from metal adherence during travel through the bath by means independent of and separable from-the so protected faces, while allowing metal adherence over a continuous unprotected portion along the length ofthe web; and thereafter coating at least the protected portions of the face of .the web with a protective material. 19. A can blank consisting of a sheet of metal having narrow bands of solder receptive material extending along opposite marginal edge portions of at least one side thereof, and non-metallic coatings extending between said solder receptive bands and overlapping said bands.

WILLIAM F. GRUPE. 

